Sorry to post here but since my ability of editing is low and my English is not very well, I think maybe some information will be useful if I put it here.
Abbadon is considered as a good counter against Batrider and Beastmaster, since the Aphotic Shield can easily purge the debuff from Flaming Lasso and Primal Roar。Although it is rare for Abbadon to be picked in tournaments, but there have been some successful examples like LaNm in EHOME. So I think the editor of this page may consider add it to the Counters paragraph. This position is also same as Oracle, as False Promise can do the same work.
Abbadon also make a well combine with Lone Druid and other similar heroes. Curse of Avernus can significantly increase the attack speed of Spirit Bear, which means increasing speed of taking down enemies or towers. Any heroes that relies on basic attack but lack for attack speed and mobility will benefit from that skill.
Sorry for posting here, but if my suggestions make some sense I will be happy.